I'd say Mariah is probably one of the artists with the most hectic release schedule in the States. Her releases are pretty quick:

1990 - Mariah Carey
1991 - Emotions
1993 - Music Box
1995 - Daydream
1997 - Butterfly
1999 - Rainbow
2001 - Glitter
2003 - Charmbracelet
2005 - The Emancipation of Mimi
2008 - E=MC2

And she has had a solo single out every year except 2002, 2004 and 2007. Maybe that's why she was so burnt out in 2001!